Thermal cut-out



(No Model.)

W. STANLEY, Jr.

THERMAL GUT-OUT.

No. 310,472. Patented Jan. 6,1885.

amen".

UNiTED S'rarss Ferarri @erica VILLIAllI STANLEY, JIL, OE ENGIJEVOOD, IEVJERSEY.

THERMAL CUT-OUT.

SPECIFICATION forming pari'. of Letters Patent No. 310,@72, datedJanuary 6, 1885.

Application filed December 5, 1882. Renewed July S, 1834. (No model.)

To all whom 'it may concern..-

Beit known that I, WILLIAM STANLEY, Jr., of Englewood, in the county ofBergen and State of New Jersey, have invented certain new and usefulImprovements in Electric Cut Outs; and I declare the following to be aclear and exact description of the invention, when read in connectionwith the accompanying drawings.

The object ci' my invention is to prevent the dangers arising from andthe loss of energy incident to overloading the conductor of an electriccurrent, and this whether by a sudden increase in the current or bylessening the resistance of the conductor, or by reason ofcross-circuiting, or for any other cause; and my invention consists ofan air-chamber so arranged in proximity to or surrounding` an electricconductor that the heat generated in the conductor by reason of anabnormal current shall effect a rupture of the conductor by expandingthe air in the air-chamber, and thereby displacing a movable bodyarranged to close such chamber, and connected with or constituting apart of such conductor.

In the drawings, Figure I is a perspective view of one form of cut-outembodying my improvements. Fig. II is a detail central section of thesame, and Figs. III and IV represent inodications thereof.

A is a tube, preferably, but not necessarily, of glass, which is closedat each end in any convenient way in the present case by blocks B, whichalso support it in proper position upon a wall, base, or bracket, C-andit is provided with a capillary passage, A, which unites the air-chamberA2 with the receivingchamber A5. Terminating in the air-chamber are twowires, D D', which constitute the conductor of an electric current. Oneof these wires, D, enters the air-chamber through the capillary passage,without filling it, however, and its end and the end of the wire D areso arranged that a globule of mercury, E, too large to pass through. thecapillary passage by reason of its own weight serves to imite them andcomplete the circuit D D. rlhe electric circuit within the air-chamberconsists, in whole or in part, of material of lower conducting-power,and therefore is of greater resistance, thanv the portions of thecircuit exterior to the air-chamber; but it has such a degree ofconductivity as to readily allow the passage of the current designed forthis circuit; hence the operation of the apparatus under the iniluenceof abnormal conditions is this: An excess ot' current produces heat inthat part of the conductor which is of low conductivity, and the heatthus generated expands the air in the air-chamber and forces the globuleof mercury which connects the terminals D and D/ into the receiverbelow, thus breaking the overloaded conductor. The chamber A, whichreceives the mercury when it is expelled from the air-chamber, may beclosed; but it is usually provided with a small opening, which willpermit the air to enter or pass out. rllhe airchamber, however, shouldbe practically air-tight, or at least to such an extent that theexpansive action of thc confined air may be utilized for the purposedescribed. 'Io reestablish the continuity of the conductor after it hasbeen ruptured, as explained, the mercury has but to be agitated, withthe lower chamber, A, uppermost, when it will ilow back into theair-chamber, and, the air-chamber being placed in the position shown, itwill again imite the terminals of the conductor.

In Fig. III, I show substantially the same dcvice as is illustrated byFig. I, the only change being that the wire D enters the air-chamber inthe same manner as the wire D, instead of through the capillary passage.

It is manifest that the mercury or other liquid which is used to closethe air-chalnber, and which is displaced by the expanding of theconiined air, may be made to effect the rupture ot' the conductor inother ways than by being, a movable part thereof, thrown out of contactwith a hxed part, and the airchainber, instead of containing, might besurrounded by, coils o'f that part of the conductor intended to beespecially sensitive to changes in the current.

I show in Fig. IV a modification of this character, in which theair-chamber G is support ed upon pivots g, and is surrounded by a helix,I'I, arranged in the electric circuit which the device is intended toguard. Heat generated in this helix will, by expanding the air containedin the chamber G, expel the mercury I therefrom, and cause this chamberto IOO roel; on its bearings and break the electric conductor at J, oneof the contacts at this point being` of the requisite elasticity topermit the bulb G to descend. Se, also, a Inovable body of othermaterial than mercury may be used to close the air-chamber, and may beconnected with the conductor by means which shall produce a break in theconductor when the movable body is displaced by the expansion of theconiined air.

That portion of the conductor which is Within close proximity to orcontained in the airehamber may, as indicated, consist of material ofrelatively poorer conductive power than the rest of the conductor-such,for iustance7 as platinum; but a reduction of the conductor incross-section will effect the same condition, which is, however, notessential to the successful operation of theapparatus.

Vhat I claim as new isl. In an electric cut-out, the combination of anair-chamber, an electric conductor arranged in such proximity to saidchamber that heat generated by the current will materially expand theconfined air, and a movable body arranged to close said chamber andconnecting with said conductor, as and 'for the purpose set forth.

2. In an elect-ric cut-out, an air-chamber provided with a capillarypassage normally closed by a liquid conductor, in combination with anelectric circuit arranged in such proximity to said chamber that heatgcnerated by the Acurrent will materially expand the conlined air, asand for the purpose set forth.

3. In an electric cut-out, an electric conductor composed ot' two partsof different conductivity, in combination with an air-chamber closed bya movable body, substantially 1

